1. Field of the Invention
This invention relates to a mold device for molding a preform incorporated into a rotary type injection blow molding machine.
2. Description of the Prior Art
A molding machine for continuously carrying out a series of operation from injection molding of a preform to blow molding of a container such as a bottle is known from Japanese Patent Publication No. 53-22096.
In a mold device for molding a preform disposed in this known molding machine, a cavity mold is moved up and down with respect to a neck mold on the underside of an upper base plate above a machine bed to open and close a mold. Therefore, when the mold is opened, a nozzle of an injection apparatus has to be released, which entails a longer injection molding cycle. In addition, the nozzle brings forth stringiness, leakage or the like depending on the kind of resin used.
In view of the foregoing, it was attempted to secure the cavity mold on a machine bed and to move a neck mold up and down. In this case, the neck mold has to be moved up and down together with a transfer plate. This poses other problems. For example, the apparatus becomes complicated in terms of other operating portions and it takes time to rotate the transfer plate immediately after opening of the mold to transfer a preform together with the neck mold to a next operating portion.